Production of emulsions or composi



Patented Oct. 9, 1945 UNITED STATES PATENT FHCE PRODUCTION OF EMULSIONSOR COMPOSI- TIONS OF OR CONTAINING ORGANIC POLYSULPHIDES AND ARTICLESPRO- DUCED THEREFROM John Rodriguez Blanco, Wylde Green, SuttonColdfield, Albert Edward Toney Neale, Erding- Sutton Coldfield,

England, a British company No Drawing. Application March 16, 1943,Serial No. 479,380. In Great Britain March 2, 1942 Claims.

reaction product which may enclose aqueous and I other impurities. Inorder to obviate this disadvantage it has been proposed to add to thereaction mixture what has been described as a dispersing agent such asfreshly precipitated magnesium hydroxide, chromium hydroxide, gelatin,glue, or a finely divided oxide, hydroxide, or carbonate of any alkalineearth metal. Other finely dispersed solids which have been used for thesame purpose include barium sulphate and aluminium silicate. Granularproducts have also been obtained by carrying out the reaction in thepresence of a water-soluble alkyl cellulose or of a mixture of eggalbumen and magnesium-hydroxide, the latter being formed in situ. Thecharacteristics of such additions appears to be that while they will notreact harmfully with the starting materials, the reaction product willadhere to them and so will separate in a granular discontinuous form ofsuspension.

We have discovered that improved results and products can be obtained byreacting the organic halogen compound in a preemulsified condition withanaqueous solution of an alkali polysulphide or alkaline earthpolysulphide. By known methods, e. g. using a colloid mill, acream-making machine, or other mechanical means affording intimatecontact and extreme subdivision it is possible to form a fine emulsionof the organic halogen compound in water containing a small proportionof water-soluble emulsifying agent, such as of a soap or of a complexsulphonate type. The stable aqueous emulsion thereby obtained containingthe emulsified microscopic droplets of the organic halogen compound inan electrically charged condition with a negative electric charge isthen allowed to undergo chemical reaction with the aqueous solution ofthe alkali or alkaline earth polysulphide, to which also a smallquantity of emulsifying agent such as of potassium oleate or of analkali salt of a complex sulphonate acid may be added.

On account of the two continuous phases be-' ing aqueous the emulsionmixes with the sodium polysulphide solution easily and freely. The needfor stirring is reduced and homogenisation of the liquid by stirring iseffected without difilculty. The reaction proceeds easily at slightlyelevated temperature and the emulsified halogen com pound disappearsreadily and completely with the formation of the desired organicpolysulphide. The freedom of the reaction mixture from relatively largevolumes of the organic chloride prevents contamination of the product byabsorption of the resulting polysulphide in unaltered halogen compound.On account of the conditions under which reaction takes place, theimmediate product is an aqueous emulsion of the organic polysulphidefree from contamination by insoluble inorganic particles.

The reduction in the amount of necessary stirring possible with theprocedure described favours the formation of the product completely inthe emulsified form, The addition of the emulsion of the organic halogencompound gradually or by instalments is also helpful in this direction.

According to this invention a process for preparing improved emulsionsof or containing organic polysulphides comprises causing a, solubleinorganic polysulphide in the form of an aqueous solution to react withone or more aliphatic organic di-halogen compounds in the form of anaqueous emulsion.

This method of bringing together the reagents is of especial advantagewhen concurrent inter.- action of a mixture of organic halogen compoundswith the inorganic polysulphide is required. The preformed mixture ofthe organic halogen compounds in the desired proportions is emulsifiedin the same way as a single halogen compound would be and is introducedinto the alkali polysulphide solution. Each droplet in the emulsifiedmixture is identical in composition with the original bulk of themixture and this method of introducing the mixture into the alkalipolysulphide or alkaline earth polysulphide ensures a more uniformproduct.

In order to purify the resulting emulsion of organic polysulphide fromalkali chloride and/or other salts which remain in solution in theaqueous medium the emulsion may be allowed to cream or settle; theemulsified particles, on account of their greater specific gravity, tendto concentrate below a layer of supernatant medium. The latter can thenbe removed from the concentrated emulsion by mechanical separation e. g.by decantation or syphoning.

In the immediately formed emulsion of organic polysulphide produced bythe reaction, the dissolved saline substances resulting concurrentlyfrom the chemical reaction assist the creaming" or.scparation. Theirpresence may lead to a reversible and temporary association of theindividual particles in the emulsion of organic polysulphide so thatloose and easily resolved compleggesmr flocculates are formed which haveincreased power of separation.

. of'th'e concentrated emulsion so separated how contain a smallproportion of protective colloid -or emulsifyinfigentj for the furtherpurifica- (4 tin, qi,...the .emulsion by separation or settling.

it may thereiore be necessary to adda small proportion of a creamingagent; such as sodium alginate to assist settling, or preferably toapply some centrifugal means of-concentration of the emulsion. By' thisprocedure it is possible to After re-dilution I obtain stable emulsionscontaining proportions of the organic olysulphide as high as 140 gramsper 100 cc. or 90% by weight. The more highly con entrated. emulsionsare of pasty consistency.

" OTher methods of purification may be adopted e. g. dialysis orelectro-dialysis aswell as other methods of concentration 6. g. byevaporation.

For the further stabilisation of such emulsions small proportions ofknown stabilising agents or s which onmmedigoo/h by weight of solidprotective colloidal substances may be added such as casein or gelatin.

The emulsions so obtained can be used in the manner of known latexprocesses, as practised a mechanical stirrer was maintained at 50 C. ina water bath. The ethylene dichloride emulsion was added gradually overa period Of half an hour with gentle stirring sufficient to causeadequate mixing of the emulsion throughout the reaction vessel as-it wasadded. Initially the emulsified ethylene dichloride was seen to dissolveand later a cloudy precipitate of the ethylene olysulphide appeared.Heating was continued at 50 C. for minutes after the addition of theethylene dichloride emulsion. The ethylene polysulphide was then in theform offlocculates of visible size which settled within a few minutes toform a concentrated suspension under a layer of mother liquor.

'The polysulphide solution was decanted from the suspension and thesuspension stirred into 500 ecs. water containing l% of potassiumoleate. After gentle stirring the flocculates were now much smaller andsettling was less -rapid. A repetition or thisg process of decantationand dilution gave a suspension" in which the separate particles were notvisible and which did not settle readily. Further'purification wascarried out by centrifuging which accelerated the settling and permitteddecantationlof the solution.

The processToscentsif uging, decanting and redilution in 1% potassiumoleate solution was repeated 3 times, after which the proportion of so-\dium salts remainin was negligible. After pourmaterial.

with rubber latex, to produce articles by spread ing, dipping,extruding, etc., in the various modifications of these-operations. Bysimple coagu.-, lation, e. g. by the addition of an acid. thepurified-emulsions can bemade to yield correspondi ingly pure organicpolysulphide products.

Eurthernioreby subjecting the emulsions pro duced by our process 3preferably under mildly alkaline conditions; e. g.

ing off the supernatant liquid, the product was removed fromlthecentrifuge as a thick white This paste was easily diluted with wate orwith a solution containing stabilisers giving an emulsion ofethylenepolysulphide which "at a concentrationpf "70 gms. per 100 ccs.was

:white in colour and of milky appearance.

tdincreased temperature.

' with the addition of a" small proportion of a vola- .tile alkali; itis possible to efiect a sort of vulcanisation" wherebyhl'ie physicalcharacteristics By way of contrast to the above the following shows theeifects obtained by the use of ethyl effe dichloride in a non-emulsifiedcondition.

A sodium polysulphide solution was-prepared as above. diluted to avolume of 400 cos. and 4 gms. of potassium oleate dissolved in it. s

The solution was maintained at C. in a flask and well stirred; 30 Ems.ethylene dichlo-' ride was added drop by drop in a non-emulsifiedcondition over a period of half an hour. Heatof the emulsified colloidalproduct are impRved 50 and consequently also} the mechanical qualitiesof the articles produced-therefrom. v

The invention-may be -.conveniently carried into efiec't as shown inthe-following .examples.

gms. sodium sulphide. Na2S.9H2O, was

' fmixed with 328 15- powdered sulphur and was considered to' predominatvery fine dispersion was thus obtained in which ccsfwater. The mixturwas boiled*for 5 hours during which the sulphur dissolved and a stablesolution 'of sodium 'polys lphide was formed. The composition ofthepo'ly lphide correspond- 'um,.Na2S4, which iii-{the solution. Thiswas filtered free of \undissolve'd impurities, diluted to 400 ccs withwater and-4 gms. potassium oleate dissolved in-it. r

32 ems. ethylene dichloride was emulsified in water by mixing it with 60ccs. 'of"ia 1% otassium oleat solution in water and passing the mixturethrough an emulsifying machine. A

droplets of ethylene dichloride settled only very slowly. e

The polysulphide solution in aflask fitted w th ing was again at 50C.and stirring was continued for a further half hour after the addition.

At the end of this time the ethylene polysulphide was found to be formedpartlyas a susprocess of decantation and dilution described I pensionsimilar to that obtained as described above, and partly as a plasticmass which contained occluded ethylene dichloride. Thisshows that theimportant'advantage according to this invention cannot be obtained bythe method in which the ethylene polysulphide is used in a non vemulsified condition."

Lfxample 2 A dispersion oi ethylene polysulphide was prepared by.chemical reaction between emulsifiedethylene dichloride and sodiumpolysulphide as in Example 1.

. After removal from the reaction vessel, the

Example 1 was carried out twice. i r

To enable the purification to be carried out further sodium alginate wasadded to give a coricentration of 0.15% in the solution; 5 ccs. ofconcentrated ammonium hydroxide was also ad ed i wax ai ed and underthese conditions settli-n diluted with/water and was caused to settle asbefore in .the presence of 1% potassium oleate,

0.16% sodium alginate and ammonia in the solution. Repetition of thisprocess of "creaming and decantation six times resulted in an emulsioncontaining 70 gms. ethylene polysulphide per 100 ccs. and substantiallyfree from the saline pared and purified by a method similar to thatdescribed in Example 1. In this case, however,

' the emulsifying agent used in place of potassium oleate was the sodiumsalt of sulphonated lauryl alcohol at present sold under the registeredtrade-mark Lorol. The concentration used was /2% of the latter and 1%glue was also used as a protective a ent throughout the preparation andpurification of the emulsion.

After purification by repeated centrifuging the emulsion was diluted toa concentration of 40' gms. per 100 ccs. and 1% of pyridine added to it.The emulsion was then transferred to a closed vessel and heated in asteam autoclave at 140 C. for 45 minutes.

The emulsion was unchanged in appearance by this treatment and wasconcentrated to a greater strength, viz., approximately 80 ems/100 ccs.by centrifuging. On drying out a layer of the concentrated emulsion at40 C. a smooth coherent film of ethylene polysulphide remained. The

properties of this film when compared with those.

of a similar film prepared from the untreated emulsion, showed that aform of vulcanisation had taken place.

The material obtained from the vulcanised emulsion had improvedmechanical and ageing properties. The after-hardening and loss ofelasticity which frequently occur in uncured ethylene polysulphide didnot develop in the cured" material even after keeping at roomtemperature for a long period.

Having described our invention, what we claim is:

1. A process for preparing emulsions of or con taining organicpolysulphides which comprises completely mixing an aqueous solution of asoluble inorganic polysulphide with an aqueous emulsion of an aliphaticorganic di-halogen compound and obtaining the reaction product in theform of a flocculate and washin the dispersed particles of saidfiocculate to decrease the amount of soluble compounds in the dispersingmedium.

2. A process for preparing emulsions of or containing organicpolysulphides which comprises completely mixing an aqueous solution of asoluble inorganic polysulphide with an aqueous emulsion of an aliphaticorganic di-halogen compound and obtaining the reaction production in theform of a flocculate, creaming said flocculate, removing the creamedflocculate from the aqueous medium and rediluting.

3. The process of claim 2 in which said flocculate is creamed withsodium alginate.

4. A process for preparing emulsions of or containing organicpolysulphides which comprises completely mixing an aqueous solution of asoluble inorganic polysulphide with an aqueous emulsion of an aliphaticorganic di-halogen compound and obtaining the reaction product in theform of a flocculate and freeing the dispersing medium of saidflocculate from dissolved impurities by dialysis.

5. A process for preparing emulsions of or containing organicpolysulphides which comprises completely mixing an aqueous solution of asoluble inorganic polysulphide with an aqueous emul sion of an aliphaticorganic di-halogen compound and obtaining the reaction product in theform of a flocculate and heating said fiocculate in the presence of avolatile alkali.

6. The process of claim 5 in which said volatile alkali is pyridine.

'7. A process for preparing improved emulsions of or containing organicpolysulphides which comprises completely mixing an aqueous solution ofan inorganic polysulphide with an aqueous emulsion of an aliphaticorganic dihalogen compound and obtaining the reaction product in theform of a flocculate.

8. A process for preparing improved emulsions of or containing organicpolysulphides which comprises completely mixing an aqueous solution ofan inorganic polysulphie with an aqueous emulsion of an aliphaticorganic dihalogen compound and obtaining the reaction product in theform of a fiocculate and then concentrating the fiocculate obtained fromthe reaction.

9. A process for preparing improved emulsions of or containing organicpolysulphides which comprises completely mixing an aqueous solution ofsodium polysulphide with an aqueous emulsion of aliphatic organicdihalogen compound and obtaining the reaction product in the form of aflocculate.

10. A process for preparing improved emulsions of or containing organicpolysulphides which comprises completely mixing an aqueous solution ofan inorganic polysulphide with an aqueous emulsion of ethylenedichloride and obtaining the reaction product in the form of afiocculate.

JOHN RODRIGUEZ BLANCO. ALBERT EDWARD TONEY NEALE. DOUGLAS FRANK 'I'WISS.

